


Body and Water

by scarletsaber (sushibunny)



Series: Makoharu Week 2016 [3]
Category: Free!
Genre: A Wild Plot Appears, Alternate Universe - Magic, Alternate Universe - Merpeople, Day 3, Gratuitous Smut, Haru's Every Fantasy Come True, M/M, MakoHaru Week 2016, Mermaid Sex, Mermaids, Merman Tachibana Makoto, One Day I Will Write Purely Plotless Smut, Some Haru x Water Action Because What Else Would You Expect From Today, SouRin mention, Water, Water Manipulation, Water Sex, smut in chapter 2, today is not that day, waterfalls
Language: English
Status: Completed
Published: 2016-09-20
Updated: 2016-09-21
Packaged: 2018-08-16 08:46:05
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 8,598
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8095636
Author URL: https://archiveofourown.org/users/sushibunny/pseuds/scarletsaber
Summary: Ever since he first met the green eyed mermaid as a boy, Haru knew he never wanted to leave his side. He loved swimming with him, listening to him talk, watching him manipulate the water around him; he loved Makoto.And now that they'd known each other for a decade- been inseparable for that long- he was ready to make that a more permanent arrangement; by becoming Makoto's mate.





	1. Chapter 1

**Author's Note:**

> My contribution to Makoharu Week 2016 Day 3: Headcanon or (NSFW) Water
> 
> (Check out all the great fanworks [HERE](http://makoharuweek2016.tumblr.com/)!)
> 
> So this completely got away from me (big surprise!). It was supposed to just be mermaid smut with some erotic use of magical water powers, but somehow plot happened. And then fluff and feels wormed their way in and I just gave up on the PWP idea. Oh well. But there is still like 4k words of smut on top of that, don't you worry; I got you and your dirty mermaid needs ;)

When Haru first met Makoto, the most surprising thing about the green eyed boy was not that he was a mermaid; Haru understood enough about the water to realize that there was more to the amazing liquid than what most people knew- and the fact that it was hiding a magical, mythical species was not something he found hard to believe. No, what he did find strange was that Makoto was swimming in the river where Haru was fishing and not out in the expansive ocean like Haru had always imagined for himself whenever his dreams allowed him to swim freer than he ever could in the waking world, pale blue tail propelling him through the salty waves in his mind. But Makoto seemed to prefer the calm and gentleness of the river over the vastness and mercurial nature of the ocean.

They had been children when they first met, Haru hooking a much bigger fish than he had ever expected. Makoto had cried at first, the sharp barbed hook caught in his delicate caudal fin, marring the pale green surface with tears and red blood. He had been more upset about the jagged rip than the fact that he had revealed himself to the human boy staring at him with wide blue eyes from the bank.

Haru had been quick to shake off his shock, however, cautiously wading into the shallow waters where Makoto had practically beached himself, and gently helping the crying mermaid- merman? merboy?- remove the hook from his tail. He had expected a quick retreat from the other boy, maybe a flash of teeth, a thick tail swung at him in retaliation, but instead he had received a bright smile, one that shone like the sun that was still high in the sky and peridot eyes the same shade as his magnificent tail gleaming up at him with a warmth that Haru would never have thought to associate with someone originating from the cold waters of the sea.

“Thank you for helping me! I’m sorry I cried so much,” the mermaid had said, and Haru was once again stunned; who knew mermaids could speak Japanese? “My name is Makoto, what’s yours?”

“Haruka…” he had answered, because even if this Makoto was a mermaid and not another human, his grandmother would still be upset with him for not minding his manners. “Call me Haru.”

“Haru! Your name is girly like mine! I like it though, it suits you, Haru-chan!”

 _What’s with the -chan?_ Haru had wondered, watching in silence as Makoto continued to chatter on. Where all mermaids this talkative?

“Do you like to swim, Haru-chan? Would you like to swim with me? It’s much more fun when you have a friend with you! I mean, if you want to be my friend, of course,” Makoto had babbled, tacking on the last part hastily, looking hesitant for the first time since Haru had removed the hook.

“...Is your tail okay?” Haru had felt like he should ask, even though every cell in his body was itching to take Makoto up on his offer.

“Hmm? Oh, yeah, it’s fine. I mean, it hurts a little, but it’ll be okay, don’t worry!”

There was that smile again, this time accompanied by a tilted head and closed eyes. Haru couldn’t help but believe him.

“...Okay.”

Makoto had trilled in excitement, reminding Haru of the sounds made by the ocean dwelling mammals in the documentaries he was so fond of watching. It made him smile a little. And then Makoto had shifted himself, pushing off the sandy embankment and deeper into the water. Haru had watched with wide eyes as Makoto extended his hand, looking up at Haru with a wide grin and Haru only hesitated for a moment, pulling off his shirt and tossing it to the shore before reaching out for Makoto’s proffered hand, palms and fingers sliding together seamlessly. And Makoto pulled Haru into the water and Haru willingly followed.

And that was how it went over the years. Haru would visit the river and secretly swim with Makoto in the warmer weather- and sometimes in the not-so-warm weather; at least until Makoto figured out that humans became sick from such activities, and then he refused to let Haru swim if it was too cold, much to Haru’s displeasure. In the winter Haru would sit at the edge of a pier or a bridge, bundled up and jealous of Makoto’s ability to continue to swim. Those months they would talk- mostly Makoto, of course while Haru listened- or just spend time in each other’s presence.

Sometimes they met in the ocean, because, as Haru learned, Makoto was actually from there, and that was where his family still lived. Haru didn’t much care which body of water they met in, as long as he was able to swim with Makoto.

Makoto was considered something of an oddity among his kind; scared of the darkness of the deep water and much preferring the more calm waters of the rivers and lakes that he could swim up from the bay. His affinity for all things human was also considered strange, and much more dangerous than his preference towards swimming grounds. Makoto had warned Haru many times, much to Haru’s continued annoyance, that it wasn’t safe for them to continue to be friends. Other mermaids- mer, as Makoto told him they preferred to be called- would not look kindly on their relationship, fearing their existence would be revealed.

Haru had adamantly refused to give him up, even if it put his own life on the line. Makoto was his best, oldest, most precious friend, and he meant more to Haru than he could say; not that Haru was ever great at speaking his feelings aloud to begin with. But how he felt about Makoto… It was special. Makoto had tried to cut ties many times as they grew up, but Haru’s stubbornness and Makoto’s innate desire to please him had always gotten Haru his way in the end. So they continued on, spending as much time together as they could- much to Haru’s satisfaction.

It wasn’t until one summer night in Haru’s second year of high school when things changed. They were swimming together in Makoto’s favorite estuary, when Makoto had suddenly frozen before moving faster than Haru had ever seen him move, pulling Haru underwater behind a rocky outcropping and covering his mouth with a webbed hand. Haru had been puzzled- and more than a little worried at Makoto’s odd behavior- but he trusted Makoto, so he stayed still and silent while his friend warily looked around. It wasn’t until Haru caught sight of flashes of color, bright red and teal, that he understood why Makoto was acting so strange.

Other mermaids.

Haru had learned a lot about mermaid- mer culture from Makoto’s chatter over the almost ten years they had known each other. He knew that the mermaids swimming some distance from them were about Makoto’s age, barely considered mature, but still a force to be reckoned with- especially the larger one. He knew that they had probably scented Makoto and were looking for him. And he knew that it would be extremely bad if they found Makoto with a human.

Even the fear running through his veins didn’t prevent Haru from needing to breath though, and his hand had flown up to clutch at Makoto’s one still pressed to his mouth. Makoto had given him a frantic look for a moment before he understood Haru’s action and with a now familiar look of concentration on his face, Makoto raised his other hand, invisible magic manipulating the water at the surface until it formed an air pocket which he then pulled down and guided over Haru’s mouth. Haru had sucked in a deep breath from the bubble, breathing out into the water gently through his nose in a practiced gesture before giving Makoto a grateful and reassuring smile.

That was another thing Haru found fascinating, yet not all that surprising about Makoto: his magic. Apparently all mer had the ability to manipulate water, though their strength and skills with it ranged widely. Makoto had never admitted to Haru what his own skill level was, saying he was okay at magic and preferring to leave it at that while a blush coated his ears, but Haru had his own suspicions that Makoto was much more adept than he let on. Pulling air bubbles from the surface so Haru could breath underwater for a time and dive deep with Makoto was only one of the amazing things Makoto had shown him over the years, and each new skill never failed to leave Haru in awe.

Once Makoto had been satisfied that Haru had enough air for a few minutes, he made the gesture that asked Haru to stay put and that he would be back. Haru had nodded in understanding, though he still watched with apprehension as Makoto swam off, heading towards the intruders to hopefully send them off before they could discover Haru.

Haru had waited anxiously until his bubble dwindled down to nothing and he was forced to either leave his hiding place or drown. He was cautious as he made his way to the surface, hugging the rock as he ascended. After gulping in a few grateful lungfuls of air, he had looked around, pleased to note that there was a substantial portion of the rock above the water, more than enough for him to sit on. Haru had heaved himself from the ocean; though he would have preferred to stay in its cool embrace, he knew better than to tempt fate and stay where he could easily be spotted by the wrong eyes. Makoto would know where to look for him when he came back… If he came back.

 _No, he’s fine,_ he had stubbornly told himself. Makoto was just waiting to make sure it was safe to return. He had never left Haru behind without coming back before, and Haru had no reason to believe he would start now. Granted, they had never been so close to being caught before… No. It was fine. It would be fine. Haru would just wait.

It was almost an hour before Makoto returned. Haru had begun to really worry, twirling his goggles around by the strap in a show of nerves as he sat on the rock, wind chilling him as it blew across his unprotected and half naked body. When oliver brown hair suddenly broke the surface with a large gasp and a cry of his name, Haru had been more relieved than he could ever remember being.

“Makoto!”

Makoto’s head had whipped around, eyes lighting up with relief as he quickly swam over, grasping Haru’s hands in a tight grip as he leaned against the edge of the rock while floating before Haru.

“Haru I’m so sorry! I didn’t think it would take so long to get them to leave me alone! It’s just that Rin’s mate is new to the area and he wanted him to make more friends, and since I’m friends with Rin, well, he wanted me to come spend time with him and Sousuke. He knows I like to swim alone- well, I like to swim with _you_ , but everyone _thinks_ I’m alone- so he thought they’d just come and join me so they tracked me here and I tried to get rid of them, but then I felt really bad, because Rin is my friend and Sousuke is his mate and he’s really a nice guy once you get to know him, so I had to talk with them for a bit. But I did manage to tell them I had promised to hunt some mackerel for Ren and Ran, and Rin hates mackerel for some reason- I know, I know, Haru-chan, you don’t need to give me that look- so they decided to finally leave, but now I feel bad for lying to them, but then I feel worse for leaving you here alone for so long and I’m just _so sorry_ Haru-chan!”

Haru hadn’t been able to help smiling softly at the deluge of words that poured out of Makoto’s mouth, a seemingly endless stream of explanations and apologies; though he had expected nothing less, really. “Makoto. It’s fine.”

“But it’s _not fine_ , Haru! This is what I keep telling you! It’s too dangerous for us to keep meeting like this! If Rin and Sousuke had seen us…”

“Your friends would hurt us? Or turn us in?” Haru had questioned, eyebrow raised in disbelief, though the rest of his expression betrayed none of the frustration and mounting fear he was feeling.

“Well, no. I mean, I don’t know. And that’s the problem! Haru… It’s not me I’m worried about. It’s you. You would be _killed_ , and I-I can’t let myself be responsible for that!” Makoto’s eyes had been full of pain as he looked up at Haru, pleading for him to listen for once. “That’s why, that’s why this has to be the last time, Haru. This… This is goodbye.”

“No.”

“Haru please-”

“I said ‘no,’ Makoto!”

Makoto’s eyes had widened in surprise. Haru hardly ever raised his voice.

“I’m not giving you up, I don’t care about the risks!”

“Haru-chan, I don’t want to do this either. But-”

“No ‘but’s! Makoto is important to me. I’m not letting anyone get between us.” Haru stared at Makoto with determinations until Makoto’s gaze softened. He felt himself flush as he contemplated his next words. “Unless you don’t feel the same…”

Makoto had frowned before some unknown emotion crossed his face. “And how do you feel, Haru?” His voice had been soft, gentler than the light waves that moved alongside him.

Haru wasn’t sure exactly what it had been that made him do what he did next. Maybe it was the way the moonlight was shining off the smattering of green scales on Makoto’s face, or the soft way he was looking at Haru, or the way Makoto’s grip on his hands tightened after he interlaced their fingers. Whatever it was, Haru would never regret leaning forward on the hard stone and pressing his mouth to Makoto’s wet and salty lips.

And he would never, ever regret the way Makoto kissed him back.

Needless to say, they never had a discussion about splitting apart again.

* * *

 “Are we there yet?”

Makoto chuckled in amusement at Haru’s huff. He really was adorable when he was impatient- which was almost always, really. “Almost, Haru-chan.”

He ignored the grumbled reply as he continued swimming, enjoying the feeling of Haru’s arms wrapped around his neck and body against his back. It had taken some convincing for Haru to allow Makoto to give him a ride on his back up the river, but Makoto had explained it was necessary for the surprise. That and the fact that not even Haru could swim properly with a blindfold on.

It had been a few months since Haru had kissed him. Winter had finally ended and it was one of the first days it had been warm enough for Haru to swim with him again. And Makoto had definitely missed it. Haru was as graceful in the water as any mer; so much so that Makoto often found himself wondering if Haru hadn’t somehow lost his tail as a child and grew legs instead. But that was ridiculous, surely. In any case, Makoto was looking forward to seeing that elegance again.

Now that the weather had warmed they could share the water once more. It had been difficult over the cold months, to say the least. They had been relegated to holding hands and stealing kisses for the most part- Haru unable to join Makoto in the water and Makoto only able to tolerate being on land for so long. It wasn’t that he couldn’t be out of the water for long periods of time; it took many hours for him to dry to the point of uncomfortableness. But in winter the air was frigid and the wind blew on his wet skin roughly, causing his scales to begin to freeze over in a short amount of time, which was not a pleasant feeling. Haru did try to help, bringing him soft and insulating human clothes to wear and blankets to drape over himself, but he could only stand the chill for so long before he had to retreat back into the sea, much to both their displeasures.

Makoto couldn’t explain why exactly he was able to stay warm in the water. He knew it was a part of his inherent magical ability, somehow able to keep the water around him warm and keep himself from freezing even as the temperature in the ocean dipped low. Haru had made a comment once about vibrating water molecules but Makoto hadn’t understood what he had meant. He did understand, however, that he was only able to expand his water heating ability so far from himself for so long- which was why Haru had only been allowed to join him in the ocean in the middle of January once. And even then Haru had still shown up with a cold the next day, much to Makoto’s distress.

But they didn’t have to worry about that now, spring-warmed water flowing past them as Makoto propelled them upstream. _And we don’t have to worry about wanting to touch but not being able to either_ , Makoto noted with a pleased sigh, taking note of Haru’s weight against his back. He wasn’t exactly sure how much touch factored into intimate human relationships, but it was a big part of mer’s, and it was starting to affect Makoto negatively to have been denied it for so long. His instincts were hounding him to cover Haru with his scent, to mark him as his own, and to have Haru do the same to him- though he knew that humans didn’t do that sort of thing, so Haru had no such drive; plus it would be dangerous for him to swim around smelling like a human. He could still dream, though.

And beyond that was the desire to make Haru his mate, in every sense of the word. Makoto would have been happy to suppress that want indefinitely, knowing things on the surface world were different- relationships seeming to change with the seasons. He would never want to force something on Haru that he didn’t want. But, as was usual, Haru had surprised him by bringing it up first. It had started innocently enough, asking about Rin and his mate, and how all of that worked for mer. And Makoto of course had answered, as best he could, anyway- though he had devolved into blushes and stutters once Haru’s questions veered into a more… _intimate_ nature.

And when Haru had all but declared he wanted to mate with Makoto when it was spring again, Makoto had promptly fainted, waking to a worried Haru hovering over him who quickly fell into quiet giggles once he realized Makoto was only overly embarrassed and not sick. Makoto had been less amused, though he hadn’t been able to stop the grin that spread across his face at the sound of Haru’s rare laughter.

That moment hadn’t been half as embarrassing though as when he had gone home later to find Rin and ask him about the… specifics of mating. He had had to field and ward off a seemingly endless amount of- mostly mortifying- questions from his red tailed friend, who was quite eager to know all about Makoto’s prospective mate. But eventually Makoto managed to dodge them, placating Rin with a promise to introduce him once his mating claim was completed. Makoto honestly had no idea how that would go- most likely terribly- but he would cross that trench when he got to it. For now, he comforted himself with the knowledge he had gained from Rin, even if he couldn’t help but flush every time he thought back to their humiliating conversation.

So that brought Makoto there, swimming upriver to a special place he had discovered a while back on one of his many forays into the waterways around the town Haru called Iwatobi. It was the perfect place to officially claim Haru as his mate, and he was extremely excited for Haru to see it. Haru would love it, he just knew it.

“Okay, Haru-chan! We’re here~!

He helped shift Haru off his back and into the water beside him. It was still quite deep- Makoto had learned ages ago to steer clear of shallow waters- so it took Haru a moment and Makoto’s supportive arm before he gained his bearings enough to pull off the blindfold. The audible gasp that left his lips made Makoto break out into a wide grin.

“Makoto…”

“Do you like it?” he asked, even though the answer was clearly written on Haru’s awed face.

“It’s… beautiful.”

Makoto couldn’t help but agree. They were treading water in a wide and deep river surrounded on either side by thick trees. The water was a deep blue, the trees a bright green. But the real splendor was the fifteen foot waterfall, flowing fast and strong in front of them.

“That’s not even the best part,” Makoto added, turning to hold a hand out to Haru, who immediately grasped it, any hesitation long gone after all their years together.

Makoto smiled, swimming backwards as he pulled Haru along, right up to the spray of the fall and then underneath and through. Haru let out a surprised cry at the shock before it turned into an amazed noise as he took in the small cave that opened up behind the waterfall.

“Makoto…”

There was a light covering of moss on the cave floor, the rock it sat on leading into the water in a smooth slope, making it easy for Makoto to haul himself up, pulling Haru up after. Light filtered in through various openings in the rock walls as well as through the waterfall, giving a soft illumination to the enclosed area. Haru looked around in wonder, unable to focus on only one spot for long.

“Haru… You mentioned, before, a-about wanting to, um, to m-mate. And I thought, only if you still want to, that is! I thought that maybe, here, we could, you know…”

“Makoto.”

“Er, yes, Haru?” Makoto looked up, face feeling hotter than he could ever hope to make the water with his magic.

Haru gave him a small smile. “I do. Want to.”

“Eh?! Really?!” He couldn’t help himself from throwing his arms around Haru in his excitement, hugging him tight before they both ended up tipping over, Makoto only registering the change in orientation when Haru let out a wheezed “ _oof_ ” when Makoto landed on him. “Ah! Sorry, Haru.”

“...It’s fine.”

Haru looked up at him then, bright blue eyes gazing at him with such love and affection that Makoto felt his heart swell. Even in the dim lighting outside of the water, Makoto could tell the pupils in Haru’s eyes were wider than normal, almost starting to eclipse the blue he loved so much- and he knew it wasn’t just from the lack of light. Makoto idly wondered if his own eyes were capable of such a feat. Would his slitted pupils dilate wide with lust in the same way? He supposed it didn’t really matter what his eyes did; he would show Haru how he felt in many other ways.


	2. Chapter 2

**Summary for the Chapter:**

> Haru learns about mermaid anatomy (and sex practices).

**Notes for the Chapter:**

> Here's the rest, freshly edited!
> 
> I honestly have no idea where this came from. Please don't blame me for this lol 
> 
> To paraphrase the immortal words of another fanfic author: I may have written this trash, but you’re the ones visiting this landfill. 
> 
> Enjoy ;)

“So. How does this work, exactly?” Haru questioned, feeling his cheeks warm. Of course he knew how sex worked, generally speaking- not like he had any first hand experience with it. But all his knowledge was human based; he had no idea how mermaids worked. Did they even _have_ sex? Haru really hoped so.

“Oh, well, um… Why-why don’t I just show you?”

Makoto was red as a tomato and Haru thought it was adorable.

“Okay.” Going with the flow had always worked best for Haru before; why change now?

Makoto slowly- almost shyly- lowered himself down until their lips touched, mouths meeting in a slow kiss. Impatient as always, Haru weaved his fingers in Makoto’s hair, tugging him closer. Makoto groaned, shifting so his tail was between Haru’s legs, arms winding around Haru’s waist and holding him against his chest.

The kiss turned heated, mouths sliding open and tongues meeting in the middle before moving back and forth, from one mouth to the other, caressing and touching as they went. Haru had been pleased when he learned that mermaids kissed similarly to humans, though there was of course usually more water involved- not that Haru minded that in the least; he might have had a thing for water, not that he’d ever admit it- though if he was being honest with himself he’d say Makoto probably already knew. He was glad they could at least start off on familiar footing; he was unsure about what would come next.

As if sensing his hesitance- which he almost certainly was- Makoto pulled back to look at him. “Are you okay, Haru?”

Haru hummed in reply, lifting his head to peck Makoto on the lips, earning himself a smile.

“I’m not sure what humans do, I’ve never, ah, seen it before. Or done it, of course. Ah! Not that I’ve done it with any mer either!”

Makoto’s unnecessarily nervous stammering had always been an endless source of amusement for Haru, and now was clearly not going to be an exception.

“I haven’t either,” Haru admitted, stroking a hand along Makoto’s cheek in reassurance, fingers gliding over the surprisingly soft scales scattered across it.

Makoto nuzzled into the caress. “We can figure it out together, yeah?”

And then Makoto’s lips were on his neck and Haru forgot how to breathe. His fingers found their way back to Makoto’s hair, grasping onto the strands as if they could keep him from falling deeper into the pleasure Makoto was wreaking along his body. He could feel Makoto’s sharp teeth gliding along his skin, never hard enough to break the surface, but with enough pressure to cause the skin to tingle in anticipation. Makoto’s tongue soon joined in, laving at the water still clinging to Haru’s collarbone as he moved lower. Haru’s hand shot to his mouth in an attempt to cover a keen when Makoto found a nipple, tongue swirling around it.

He must have been largely unsuccessful, as lidded green eyes looked up at him. Makoto’s eyes seemed to glow like a cat’s in the dim light, shaded by the fringe of his hair. It sent a shiver running down Haru’s spine and he did nothing to stop the moan that came this time as Makoto lapped at his nipple, maintaining eye contact the entire time. Makoto’s other hand wandered up his chest, paying homage to the neglected bud on the other side, causing Haru to writhe beneath him.

“Good?” Makoto breathed hotly against Haru’s wet skin, making heat pool deep down in Haru’s gut.

Haru could only moan out his name, throwing his head back against the moss carpet as Makoto’s mouth returned to its work.

Suddenly it felt like Makoto’s hands were everywhere, touching his thighs, his hips, his sides. It felt amazing. But also impossible. Haru opened his eyes, not realizing he had closed them in the first place and tilted his head back up, only to groan in surprise- and arousal. Makoto hadn’t grown any extra sets of hands, no. But he was manipulating the water from the small pool behind the waterfall, creating tendrils- _fingers-_ of water that now caressed Haru’s body alongside Makoto’s own.

“Makoto- what-?”

Makoto looked up at his ragged voice, though his fingers- both humanoid and water- continued in their fondling. “Yes, Haru? This isn’t too much, is it?”

Haru had never heard Makoto’s voice so low, so husky before, and he couldn’t help whimpering at the mere sound. “No… I, _more_.”

The smirk Makoto gave in response would look ridiculous in any other situation, but now… Now it just made his jammers feel unbearably tight.

“Where… Where did you learn-?” Haru managed to ask, writhing beneath Makoto as he kissed lower down Haru’s abdomen, tracing every muscular line he came across with his tongue.

“Hmm? You mean the water?”

“Mm!”

“Ah, well, apparently magic is, um, incorporated in mating quite, uh, freely,” Makoto answered, words vibrating across Haru’s stomach as Makoto spoke against his skin. “We usually, uh, mer, that is, usually do this sort of thing underwater. But…” he trailed off, not needing to state why now was different.

“I can… in the water…” Haru stammered, breathing hard as Makoto tongued a line along the waistband of his jammers.

“No, this is fine, Haru. I want it to be the best for you,” Makoto said, looking him in the eye to make sure Haru understood he meant it. “We can always… try in the water next time.”

If Haru hadn’t been hard before he would have been at those words. There was just something about combining Makoto and the water that was highly… arousing to him.

“Now, I need to take these off, right?” Makoto asked, plucking at the elastic of the swimsuit.

Haru wordlessly lifted his hips in response, watching with a heated gaze as Makoto pulled them down and off, placing them gently off to the side on a rock. Haru flushed red from his scalp to his chest as Makoto stared fixedly at his erection, looking at it as if he was making a study of it.

“Hey. Quit staring.”

“Eh? Oh, sorry, Haru-chan!” Makoto said, rubbing a hand behind his neck in embarrassment. “It’s just, I’ve never seen a human one before.”

The water tendrils returned to chest then, as if in apology, gliding around his nipples and up to tenderly caress a cheek, filling Haru with a mix of lust and affection.

“Is it much different? From yours?”

“Er, um, well, yes and no?”

“Makoto.”

Sorry! It’s just… Well, the shape is similar, I guess? But yours appears more… rigid.”

 _Rigid?_ Haru wasn’t sure what that meant. He tilted his head, attempting to see what Makoto was implying when he realized that while Makoto had always been naked- except when Haru had dressed him up during the winter- Haru had never once seen any indication of his… genitalia.

“Show me.”

“Eh?! Haru!”

“I want to see it.” Haru all but demanded, propping himself up on his elbows.

“Haru~!”

Haru refused to budge, however, remaining firm in his order of ‘I showed you mine so you show me yours.’

“Ugh, fine!” Makoto huffed, knowing how useless it was to argue with Haru when he got that way.

The water tendrils fell away as Haru watched intently as Makoto shifted, rolling over and next to Haru until he was in a similar position, leaning back on his arms. Haru’s eyes wandered down Makoto’s chest, appreciating the firm muscles there not for the first time before moving further to where skin met scales. Still, there wasn’t anything out of the ordinary that he could see, and a quick glance down the tail confirmed it.

“Makoto.” Haru was losing patience.

“Haru, please! It’s not that easy. It doesn’t just… sit out there all the time like yours,” Makoto pouted, face once again a bright red.

“Okay,” Haru allowed, inching closer to Makoto. “Tell me how to bring it out.”

“Are you sure? You don’t have to-” Makoto stuttered, shifting the end of his tail nervously.

“Makoto. I want your cock. Now.”

With a mix of a whine and a moan, Makoto reached out, grabbing Haru’s hand and sliding it down his body below the scale line. “Here,” he husked, tracing Haru’s fingers over a slit he had never noticed before.

When Makoto’s hand retreated, Haru’s finger tentatively traced the opening, feeling how the scales along it curved slightly inward, marking its location if you knew what you were looking for. At Makoto’s encouraging moan, he increased the pressure of his touch, circling the area until he felt a new wetness on his fingers that wasn’t from the water lingering along Makoto’s scales. A glance up at Makoto’s blissed out face told him that this was to be expected, so he continued his exploratory touches, finger occasionally teasing further into the dip in the scales.

Once he felt confident enough, Haru pressed harder, letting his finger slide into the slit down to the first knuckle, watching Makoto’s face closely for a reaction. He was not disappointed when Makoto’s eyes shot wide, Haru’s name a breathy gasp escaping his lips.

“Is this okay?”

“I… Yeah, it’s okay. I’ve never, but… Feels good.” Makoto sighed, leaning forward to capture Haru’s lips in a kiss, moaning into his mouth when Haru pushed his finger deeper.

Deciding not to push his luck, Haru stuck to sliding the finger along the length of the opening, keeping the tip inside as he moved his hand back and forth. Makoto’s kisses became harder and more heated, teeth occasionally nipping at Haru’s lips and tongue, which Haru found he quite enjoyed. After a few minutes though he felt a new resistance against his finger, even though he hadn’t tried to push in any deeper. Perplexed, he broke the kiss so he could look down, withdrawing his finger and staring wide eyed at the sight before him.

A long, pinkish… _thing_ was beginning to protrude from the slit. As Haru watched in amazement it continued to push out, writhing around as it met the cool air of the cave. Haru looked up at Makoto when a muffled “ _now who’s staring?_ ” met his ears and he realized that the thing must be Makoto’s cock.

Makoto had been telling the truth before; it was pretty similar to Haru’s own. It was of a similar width and length, though Makoto’s was probably a bit longer- it was difficult to tell since it kept wriggling around- they were both flesh-toned with shades of pink, and had bulbous heads. But where Haru’s hardon was, well, _hard_ , Makoto’s wasn’t. Or at least it didn’t appear to be, what with the way it was waving around, curling and uncurling in on itself. But then again, it also didn’t look exactly soft either, at least not like Haru was when not aroused.

_Well, only one way to find out._

“ _Haru_!”

It was like a tongue, Haru decided. It could be firm or moldable as it wanted, which was pretty intriguing in Haru’s opinion. He wasn’t sure what Makoto’s objection was about, he was only holding it. And squeezing it. Maybe rubbing it a little. Nothing much, really.

“It’s not fair… If Haru has all the fun.”

Suddenly Haru found himself on his back again, Makoto pressed against his right side as a webbed hand wrapped around Haru’s previously forgotten erection. Haru found himself groaning into Makoto’s open mouth, tongue working its way inside at the opportunity and tangling with his own. The water tendrils appeared again, Makoto having regained enough focus to conjure them up. Haru wasn’t sure if he should be pleased or annoyed as they ran up his sides, stroking every inch of skin they could reach. A particularly curious tendril worked its way between Haru’s legs, fondling his balls and drawing a gasp.

Pleased, then.

Haru groaned when Makoto’s hand disappeared from his cock, moving to wrap around his lower back, twisting Haru onto his side to face Makoto. His disappointment didn’t last long, however, as Makoto’s seemingly prehensile cock literally wrapped itself around his own and began a rhythm of alternately squeezing and sliding up and down.

“Makoto, fuck-”

“ _Haru…_ ”

Haru tore away from the kiss, panting heavily. “Gonna… cum soon, if you keep- Ah!”

“Ha, do you not, mm, want to?” Makoto asked, sounding as affected as Haru.

“How… Is this how you- you mate?” Haru managed to gasp out, hips jerking against Makoto’s tail.

“Oh.” Makoto slowed his pace, water tendrils falling away again as he considered Haru’s question- and the unspoken request behind it. “Well, not exactly. That involves, um, penetration,” he said sheepishly, and Haru thought it cute that Makoto could stammer while talking about sex when he had his cock literally wrapped around Haru’s.

“Which…?” It was Haru’s turn to fumble with his words.

“Um, it doesn’t matter as far as I know, who does what,” Makoto said, giving a shy smile. “I don’t mind, either way. As long as it’s Haru.”

Haru wasn’t sure how he had enough blood leftover to make his entire face flush when he was so achingly hard, but there he was. He settled for humming in agreement- and averting his eyes. At least he had a chance to learn more about Makoto’s body again. “Where…?”

“Hm? Oh! Uh, here,” Makoto said, unwrapping himself from Haru’s length and guiding Haru’s hand down just below the opening his cock was protruding from.

It felt similar to the other one, though smaller. Haru trailed his finger around the opening as he had earlier- noting he didn’t receive a reaction even close to the same caliber from Makoto this time- before pressing inside. It was warm around him but not even damp, and he could feel Makoto’s entire body clench in the wince he gave.

“It’s not wet.”

Makoto gave him a curious look. “Um, well, no. It’s not supposed to be?”

Haru withdrew his finger with a frown, though he quickly moved his hand up to Makoto’s curled up cock, stroking it in apology. “I don’t have any lube. We can’t then.” He couldn’t help the disappointment coloring his voice at the realization.

“Oh, is that what humans do?”

Haru just gave him a look, not understanding.

“I mean, when we, that is, we don’t need…” Makoto pulled Haru’s hand off of his cock, gesturing at it. “Ah, it’s, er, self-lubricating…”

Haru looked down and noticed that there did appear to be some sort of viscous fluid coating the length. Now that he thought about it, when Makoto had rubbed their cocks together earlier it had been rather smooth and wet. Haru had just attributed it to the water around them, but apparently he had been wrong. “Convenient.”

“Eh, I guess?”

“You do it, then.” Haru shifted onto his back again, spreading his legs and looking at Makoto expectantly.

“...Are you su-”

“Yes.”

Makoto chuckled. “Okay then, Haru-chan.”

“Don’t call me -chan when we’re having sex,” Haru grumbled, turning his head away in embarrassment.

“Alright, _Haruka_.”

Haru was going to blame the shudder running through his body on the fact that Makoto had spoken right next to his ear and not the way the name he usually hated sounded in that deep tone.

Before he could protest, however- which he definitely was planning to do- Makoto had moved between his legs again and was trailing his hands along Haru’s thighs. Makoto spread his legs further, moving gentle hands along the soft skin between Haru’s legs, trailing down until he reached the small ring of muscles there, circling it slowly with a finger.

“Here?”

If Makoto didn’t sound so genuinely unsure Haru probably would have smacked him for teasing. But this was Makoto, and Haru knew he wouldn’t do that about this- at least not for their first time. Haru had a brief realization that his body was really just as foreign and strange to Makoto as Makoto’s was to Haru, and a wave of fondness washed over him for the mermaid who had changed his life so very much.

“Yes,” Haru breathed, anticipation setting him on edge. He wasn’t exactly sure how this was going to work, but he trusted Makoto implicitly.

Makoto hummed an acknowledgement, kissing Haru’s thigh and then the many water fingers were back, gliding and caressing Haru’s entire body, helping him relax again. They encircled his cock, making sure he stayed hard and ready, spreading the mix of precum and leftover natural lubricant from Makoto along the shaft, making Haru moan. They worked up his legs, soothing the tensed muscles, moving up along his sides to his chest, thrumming his nipples to hard points and keeping them that way. Makoto was using his magic to distract Haru through pleasure, and Haru found he couldn’t bring himself to mind.

And then he felt that same oddly firm wetness against his rim, slowly pushing inside, and his breath caught in his throat when he looked down and saw it wasn’t a part of Makoto, no, it was a tendril- a tentacle of water Makoto had brought to life. Makoto was going to fuck him with the water and the thought almost made him cum.

The slow press of the magically solid liquid made him groan, the thought more arousing than the actual physical feeling. There was pressure, but not an uncomfortable amount. Mostly it just felt strange. Haru supposed he should find it more weird than he did, that the tendril was solid yet not ice, that it retained its shape yet it also left behind moisture, wetting his skin and insides. But he was very familiar with Makoto’s magic by then and all he could bring himself to think about was how good it felt when it moved up inside of him and _pressed_.

“Ah, I was wondering if humans were the same,” Makoto said, voice sounding oddly breathless for someone who wasn’t actually touching Haru himself; though Haru supposed concentrating on using so much magic at once was taxing on its own. “Rin told me there was a, er, good spot inside; guess he was right.”

“I don’t want to- ah!- talk about Rin,” Haru grumbled, fingers digging into the moss underneath him as the water continued its perusal of his prostate.

“Right, right, sorry,” Makoto chuckled, grinning down at him. “You really do love the water, Haru-chan,” he observed, voice slipping again into that low range that made Haru’s toes curl. “Does it make you feel good? Do you like the water touching you all over?”

Haru thought the answer was pretty obvious, given the way his cock twitched at the words.

“Mmm, I bet I could make you cum just using my magic. What do you think, Haru-chan?”

He was going to reprimand Makoto for the nickname, he really was, but then another tendril of water was working its way inside of him and he could only gasp.

“Ah, but I don’t think I want that. I want to make Haru cum myself.”

Haru couldn’t help the way his hips thrust up as the tendrils around his cock tightened, gripping him in an almost painful, but definitely pleasurable way. His moans were getting louder then, broken gasps and cries echoing off the walls of the cave. A keen of Makoto’s name was cut off by a wet prodding at his lips, and then another tendril was inside his mouth, running along his tongue as if it was mimicking Makoto’s own.

“Ah, we can’t have you getting too loud now, Haru-chan,” Makoto teased, grinning down at Haru as he twisted his hips, giving himself access to his neglected cock, giving it a few leisurely strokes as Haru watched with lust-hazed eyes. “Do you think you’re open enough for me now?”

Haru could feel the two tendrils moving in duet inside him, pulsing and twisting, pushing and spreading him wider. The ache he had felt briefly was gone, replaced by the constant rush of pleasure from the feeling of fullness and his prostate being stimulated. He nodded, moaning around the water in his mouth.

“Haru…” Makoto groaned loudly, the magicked water suddenly dissipating, returning to its original form and splashing Haru in cool wetness. Thankfully, Makoto had the foresight to remove the tendrils from inside him first, or else Haru would have been fighting not to drown- and feeling quite uncomfortable down below. “Is it okay…?”

Haru looked up with heavily lidded eyes as Makoto slid over him and settled between his legs, cock twining against his hole but not pushing in. Haru reached up to pull Makoto down, kissing him heatedly in answer.

The first press inside was strange, but not unpleasant. Haru imagined it would feel different if it were another human, but he couldn’t help but think this was better. Makoto’s cock was flexible, and it glided easily inside without needing to force its way in. And the way it could curve on its own to find that spot again was definitely a plus.

Twin moans filled the cave as Makoto settled inside him, pressed as deep as he could reach. Haru lifted his legs, wrapping them around Makoto’s hips, pulling him as close as possible before rocking against him, wordlessly encouraging him to move. And of course Makoto obliged, hands planted on the ground to give himself leverage as he moved his hips, thrusting in and out of Haru while moving his cock independently around inside him.

“Haru~... You feel… amazing,” Makoto gasped, head falling down against Haru’s shoulder, breath leaving him in harsh pants.

“Makoto- ah- yes!”

Haru was so close already, Makoto’s water-play having driven him near the edge. He knew it wouldn’t take much more, but he was determined to bring Makoto over with him.

“I-I can feel you, twisting inside me… So good, Makoto,” he moaned, twisting his neck to nudge Makoto into a kiss, swallowing his groan. “So close. Cum with me.”

“Haru…”

Makoto’s pace sped up and Haru could swear he felt Makoto swell inside him; maybe that was another mer thing. Haru did his best to help Makoto along, clenching his muscles around him, running his hands along Makoto’s muscular back- paying close attention to the scattered scales he found every now and then- and then moving around to thumb his nipples, earning a sharp gasp.

“Haru!”

It only took a small pinch from Haru and Makoto reached his peak, cock suddenly extending straight, going rigid as he released inside Haru, who gave a cry at the feeling, body tensing up as he too came, painting their stomachs white. It took a long few minutes for them to come down from their highs, panting and sweaty, yet oh so relaxed and sated.

Haru gave a small wince as Makoto’s cock left him, retracting back into its slit, and that was all it took for Makoto to fall into what Haru referred to as his Mothering Mode.

“Oh no, Haru! Are you okay?! Was I too rough? Did I hurt you?!”

Haru stared blankly up at the roof of the cave as Makoto patted down his body, as if he was searching for injuries. “‘M fine. Liked it.”

“O-oh… Well, me too,” Makoto said softly, and when Haru looked at him again he was smiling wide, and looking at Haru with such devoted affection it made his heart ache.

“Embarrassing…”

Makoto chuckled, shifting so his tail was on one side of Haru and cuddled into him, careful not to put too much weight on him.

“So… Are we mates now?” Haru wondered, looking at Makoto out of the corner of his eye.

“Well, officially, yes. But I like to think we became mates when you refused to let me leave you.”

Haru’s eyes widened at the soft look Makoto was giving him and he had to turn his head away before his face caught fire. Makoto’s giggle at his embarrassment did nothing to help.

They laid there like that in each other's arms for a long time, just enjoying being together after going so long with only brief touches and kisses. Eventually Haru began to squirm, the remnants of their passion starting to feel uncomfortable.

“Haru? What’s wrong?”

“...Sticky.”

“ _Oh_.” It was Makoto’s turn to be red. “Ah, well, let me help!”

A warm wave of water flowed over them both before Haru could say a word, washing away all evidence of their time together. Haru said nothing when he felt a tendril once again creep along his rim, dipping inside to clean him gently, though they both knew what was happening since Makoto directly controlled his water creations; and if Haru had ever had any doubt about that fact it was erased by the way Makoto ducked his head against Haru’s shoulder in rather misplaced embarrassment.

Once he was satisfied, Makoto released the water, curling around Haru once more, letting his long, translucent caudal fin flop up along Haru’s hip. Haru’s eyes were drawn by the movement, and he frowned as his attention was once again caught- like it always was- by the small scar in the otherwise pristine fin.

“Why did you never heal that?” he asked, finally voicing the question that had plagued his mind for nearly a decade.

“Hmm?” Makoto asked, following Haru’s line of sight down his tail. “Oh, that? I didn’t want to get rid of it.”

“Why?” Haru asked incredulously. He couldn’t imagine why Makoto would want such an ugly thing marring his tail. Sure, Makoto wasn’t really the type to focus on outer beauty like one of Haru’s friends, but it seemed ridiculous to keep it around when mer had the ability to heal much more effectively than humans.

“Because it reminds me of Haru. And how we met,” Makoto said with a grin, as if it were obvious. “It was the happiest day of my life. Well, before today, I suppose.”

If Haru had thought he had turned as red as possible earlier he was mistaken; clearly this was the peak of blush, nearly his entire chest pinking in addition to his ears and face in response to Makoto’s words. He mumbled something in response, head buried in Makoto’s neck.

“Hmm? What was that?” Makoto asked, stroking Haru’s hair in a calming manner.

“I said, ‘I love you,’ you idiot.”

Haru knew Makoto was grinning widely without even looking.

“I love you too, Haru-chan!”

“Mm.”

“Hey, uh, Haru?”

“What?”

Makoto cleared his throat nervously. “I, uh, promised Rin I would introduce you to him. Tomorrow, actually. Surprise?”

“ _What_.”

“I’m sure it will be fine! I actually spent all winter telling him stories about humans, mostly stuff you told me, and now he’s super interested in them! Actually, maybe a little too interested; he’s been visiting the docks a lot to listen to fisherman gossip, and he’s kinda picked up on some of their slang. It’s, um, interesting? Sousuke is kinda not too happy about it though and he might kinda blame me? But I’m sure it’ll be okay, they’ll definitely like you when they meet you! But, maybe don’t tell Rin I said I thought you might be faster than him in the water, he’ll definitely take that as a personal challenge. And I mean he won’t let you alone until he beats you. It seems endearing at the start, but after the first fifty times it can really wear on you. Not that I don’t love Rin and all! As a friend, I mean! Just a friend! You’re my only mate, Haru, for always, and you don’t have to worry about that! Anyway, now, with Sousuke, you should probably avoid direct eye contact for the first few visits-”

Haru sighed, closing his eyes as he listened to Makoto ramble on and on about his friends and their quirks. It might be complicated, this love they shared, crossing species lines. But Haru knew all the trouble- and apparently upcoming annoyances- would be worth it. As long as he had his green eyed boy by his side.

**Notes for the Chapter:**

> ...Is this considered tentacle porn? Did I just write _Makoharu_ tentacle porn? Welp, there’s certainly no coming back from this!


End file.
